RFR: 8332547: Unloaded signature classes in DirectMethodHandles [v2]

[Vladimir Ivanov]

On Mon, 3 Jun 2024 19:36:58 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> JVM routinely installs loader constraints for unloaded signature classes when method resolution takes place. MethodHandle resolution took a different route and eagerly resolves signature classes instead (see `java.lang.invoke.MemberName$Factory::resolve` and `sun.invoke.util.VerifyAccess::isTypeVisible` for details). 
>> 
>> There's a micro-optimization which bypasses eager resolution for `java.*` classes. The downside is that `java.*` signature classes can show up as unloaded. It manifests as inlining failures during JIT-compilation and may cause severe performance issues.
>> 
>> Proposed fix removes the aforementioned special case logic during `MethodHandle` resolution. 
>> 
>> In some cases it may slow down `MethodHandle` construction a bit (e.g., when repeatedly constructing `DirectMethodHandle`s with lots of arguments), but `MethodHandle` construction step is not performance critical.  
>> 
>> Testing: hs-tier1 - hs-tier4
>
> Vladimir Ivanov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Renaming: isTypeVisible -> ensureTypeVisible

Thanks for the reviews, Jorn and Chen.

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PR Comment: https://git.openjdk.org/jdk/pull/19319#issuecomment-2146542294